Neanderthals' main food source was definitely meat

Researchers describe two late Neanderthals with exceptionally high nitrogen isotope ratios, which would traditionally be interpreted as the signature of freshwater fish consumption. By studying the isotope ratios of single amino acids, they however demonstrated that instead of fish, the adult Neanderthal had a diet relying on large herbivore mammals and that the other Neanderthal was a breastfeeding baby whose mother was also a carnivore.